Significance of finger coldness in hand-arm vibration syndrome

Objectives To evaluate the relationship between subjective symptoms of coldness in fingers and peripheral circulation in patients with hand-arm vibration syndrome (HAVS). Methods Thirty-five male patients confirmed to have HAVS as an occupational disease took part in this study. Their mean age was 62 years (SD 5) and all were chain-saw operators exposed to vibration for an average of 25 years. Their annual health examination included the history of their daily habits (smoking, drinking, and therapeutic exercise), report of subjective symptoms such as coldness, numbness and tingling in the fingers, and a physical examination; laboratory tests consisted of skin temperature measurement, and pain and vibration perception under conditions of cold provocation. A frequently used method of cold provocation, immersion of the left hand up to the wrist in water of 10°C for 10 min, was used. Results Finger coldness was classified into 3 groups according to its severity: mild group (n=8), moderate group (n=17) and severe group (n=10). There was no significant difference in age or occupational background between the groups. A significant association was found between finger coldness and prevalence of Raynaud's pheno menon (p<001, χ²). The mean skin temperature was significantly lower with the severity of finger coldness (ANOVA, p<0.05). In the cold provocation test, there was no significant difference between skin temperature and coldness at 5 min and 10 min after immersion, though a difference was observed immediately after immersion. No significant difference was observed in the relationship between finger coldness and vibrotactile threshold before, during or after the cold provocation test. Conclusions The severity of coldness in the fingers is significantly related to skin temperature. The severity of finger coldness reflects the extent of peripheral circulatory vasoconstriction. Coldness in the fingers may be a good warning of potential problems in peripheral, circulatory function.     

振动性白指—局部受冷和振动负荷后的末梢循环表现

本研究分为三个组:(1)振动白指组(29例);(2)振动无白指组(105例);(3)对照组(60例)。 研究表明:振动白指组冷水试验的白指再现率为10％,而振动无白指组和对照组无一例出现白指;Ⅰ期振动性白指患者的皮温恢复时间延长者占40％,而Ⅱ期和Ⅲ期振动白指患者皮温恢复时间延长者均为100％;振动白指组的指血流图平均波辐高度冷水试验后显著低于冷水试验前(P<0.01),而振动无白指组和对照组没有这种差异。 本文讨论上述试验在振动性白指诊断中的意义。     

Analysis of subjective symptoms of coldness and numbness in the upper and lower limbs among patients with vibration syndrome

Coldness and numbness of the lower limbs in patients with vibration syndrome were studied in correlation with the frequency of attacks of vibration-induced white finger (VWF), coldness and numbness of the upper limbs, and awakening at night due to numbness of the arm. Subjects were 229 patients aged 50-69 years without disease other than vibration syndrome who had mainly operated chain saws. The present study showed that patients with more frequent VWF attacks had a higher prevalence and frequency of coldness in the fingers, awakening at night due to numbness of the arm, and coldness and numbness in the legs. Particularly patients having almost daily attacks of VWF had a high prevalence of these symptoms. Positive correlation was observed in prevalence and frequency between coldness of the fingers and that of the legs, and between coldness and numbness in the legs. The prevalence of VWF, numbness and coldness of the fingers, and coldness of the legs was higher the longer the total chain saw operating period. The present findings suggest that patients with severe circulatory disturbances in the upper limbs have severe circulatory disturbance in the lower limbs. Further studies on circulatory disturbances in the lower limbs are indicated, and their mechanism involved should be also pursued from the pathogenetic point of view.     

Activation of blood coagulation and fibrinolysis in vibration syndrome

Summary The pathophysiology of peripheral circulatory disturbance in patients presenting with vibration syndrome was studied from the viewpoint of blood coagulation. Plasma levels of fibronectin (FN), vitronectin (VN), thrombin-antithrombin III complex (TAT), and ₂-plasmin inhibitor-plasmin complex (PIC) were measured in 23 subjects who showed no evidence of vibration-induced white finger [VWF(–) group] and in 24 patients who presented with VWF [VWF(+) group]. In the VWF(–) group, plasma FN concentrations were elevated but plasma TAT and PIC levels were within the normal ranges. In the VWF(+) group, plasma FN concentrations were normal but plasma TAT and PIC levels were significantly elevated. In both groups, plasma VN concentrations were similar to those in normal controls. For purposes of comparison, 32 patients presenting with diabetes mellitus were also studied. They were divided into 2 groups, 13 subjects who showed no evidence of angiopathy [complication(–) group] and 19 patients who presented with angiopathy [complication(+) group]. In the complication(+) group, plasma TAT and PIC concentrations were significantly elevated, as in the VWF(+) group. These results suggest that in vibration syndrome, vibration, cold stimulus, or other factors first injure the vascular endothelium, resulting in a rise in plasma FN, and that in the VWF(+) group, augmentation of coagulation and fibrinolysis induces a state of compensated disseminated intravascular coagulation (DIC).     

Autonomic and peripheral nervous system dysfunction in workers exposed to hand-arm vibration: a study of R-R interval variability and distribution of nerve conduction velocities

Summary To assess the effects of vibrating-tool operation on the autonomic and peripheral nervous system, we measured the variability in the electrocardiographic R-R interval (CV_RR) and the distribution of nerve conduction velocities (DCV) in 24 men who were vibrating-tool operators and in 17 healthy adult men (control group). Of the 24 tool operators, 13 had a history of vibration-induced white finger [VWF(+) group] and 11 had no such history [VWF(–) group]. Two components of CV_RR, i.e. C-CV_RSA and C-CV_MWSA, which have been considered to reflect parasympathetic and sympathetic activities, respectively, were also examined. Both the CV_RR and the C-CV_RSA in the VWF(+) group and the CV_RR in the VWF(–) group were found to be significantly depressed as compared with the control values; moreover, a significant difference in the C-CV_RSA was observed between the VWF(+) group and the VWF(–) group. The faster DCVs and the sensory median nerve conduction velocity were significantly slowed in the VWF (+) and VWF(–) groups. The C-CV_MWSA was significantly correlated with most of the DCV parameters and with the median nerve conduction velocities in all 24 vibrating-tool operators. These data suggest that operation of vibrating tools, which involves exposure to combined stressors of local vibration, heavy work, climate, and noise, affects both the faster myelinated nerve-fiber activity and the parasympathetic activity; the sympathetic activity at rest in workers exposed to hand-arm vibration may be related to depression of peripheral nerve conduction.     

Rheological and immunological findings in dockers with vibration-induced white fingers

Summary The aim of the present study was to characterize theological and immunological features involved in the pathogenesis of vibration-induced white fingers (VWF). Plasma viscosity, at two shear rates (580 s^–1 and 1164 s^–1), levels of immunoglobulins (IgG, IgM, IgA), circulating immune complexes, rheumatoid factor, antinuclear antibodies, fibronectin, fibrinogen, hemoglobin and erythrocyte sedimentation rate were analysed in 30 male dockers with VWF and in 30 healthy male referents unexposed for hand-arm vibrations. Decreased plasma viscosity was observed among the men with VWF, although formal significance (P < 0.05) was only obtained at shear rate 580 s^–1. The decrease was mainly seen among smokers. In the study there were no significant differences between the VWF group and the referents with regard to immunoglobulin levels, autoantibodies and other plasma proteins. From the study it is concluded that workers with VWF may have a decreased plasma viscosity. The biological relevance of this observation is uncertain and deserves further study.     

Relation of haemostatic function, neurovascular impairment, and vibration exposure in workers with different stages of vibration induced white finger.

Haemostatic function and neurovascular symptoms were investigated in 67 workers exposed to vibration and 46 comparable referents. Of these 65.6% of vibration workers complained of neurological disturbances (stages 0T, 0N of Taylor's classification for vibration induced white finger (VWF) and 20.9% suffered from Raynaud's phenomenon (stages 1-2-3). The severity of the staging symptoms showed a close relation with an index of vibration dose computed on the basis of vibration measurement and individual exposure time. Indices of platelet aggregation, both in vitro and in vivo, antithrombin III, fibrinogen and fibrinopeptide A levels were not different in the exposed workers compared with the referents. No relation was found between haemostatic parameters and the severity of VWF. Exposed workers responded to a cooling procedure with a more pronounced vasoconstriction in the digital vessels than the referents, as indicated by delayed recovery time of finger skin temperature after the cold test. These findings suggest that both in the early stages (0T, 0N) and in more severe stages of VWF (stages 1-2) cold induced hyperreactivity in the digital vessels and Raynaud's syndrome are vascular disorders of functional origin occurring without any prethrombotic alterations.     

Relation of haemostatic function, neurovascular impairment, and vibration exposure in workers with different stages of vibration induced white finger

Haemostatic function and neurovascular symptoms were investigated in 67 workers exposed to vibration and 46 comparable referents. Of these 65.6% of vibration workers complained of neurological disturbances (stages 0T, 0N of Taylor's classification for vibration induced white finger (VWF) and 20.9% suffered from Raynaud's phenomenon (stages 1-2-3). The severity of the staging symptoms showed a close relation with an index of vibration dose computed on the basis of vibration measurement and individual exposure time. Indices of platelet aggregation, both in vitro and in vivo, antithrombin III, fibrinogen and fibrinopeptide A levels were not different in the exposed workers compared with the referents. No relation was found between haemostatic parameters and the severity of VWF. Exposed workers responded to a cooling procedure with a more pronounced vasoconstriction in the digital vessels than the referents, as indicated by delayed recovery time of finger skin temperature after the cold test. These findings suggest that both in the early stages (0T, 0N) and in more severe stages of VWF (stages 1-2) cold induced hyperreactivity in the digital vessels and Raynaud's syndrome are vascular disorders of functional origin occurring without any prethrombotic alterations.     

A four-year follow-up study on subjective symptoms and functional capacities in workers using hand-held grinders.

Fifty-three grinders in the metal industry were re-examined 4 years after their first examination. Information about age, occupation, daily vibration exposure, drinking and smoking habits, and presence of subjective symptoms such as vibration-induced white finger (VWF), and numbness and pain in the fingers was collected during the first and second examination. Cold provocation test (10 degrees C/10 min) was also employed to evaluate disturbances in the peripheral circulatory and peripheral nerves in all subjects. The frequency-weighted vibration acceleration of various types of hand-held tools was measured. There was no subject with VWF at the first examination; however, during the course of follow-up, two cases (3.8%) of VWF with latent interval of more than 25 years were diagnosed. Prevalence of numbness in the fingers and shoulder stiffness was significantly higher at the second examination. When the prevalence of subjective symptoms was tested by the subjects' total operating time (TOT) during the 4-year follow-up period, those whose TOT was equal to or more than 2500 hours showed higher prevalence compared to the other subgroup. The paired values of recovery rate of finger skin temperature and vibration sensation threshold after the cold water immersion test were significantly different at the first and second examination. On average, the diminution of hand-grip force during the 4-year follow-up course was 7.4%; the difference being significant at 0.01 level. Significant differences in the paired data of pinching power and tapping ability could be detected. The frequency-weighted vibration acceleration of various tools was in the range of 1.1-4.6 m/s2. It was concluded that: (1) prolonged occupational exposure to the vibration of hand-held grinding tools should be considered as a risk factor causing disturbances in the hand-arm system of the operators; (2) the results of recovery rate of finger skin temperature and the vibration sensation threshold seemed to be appropriate indicators for the assessment of peripheral vascular and peripheral nerve disturbances in workers exposed to hand-arm vibration; and (3) to reduce the subjects' physical stress, attention should be paid to ergonomic factors.     

Heart rate variation and serum dopamine-beta-hydroxylase activity in workers exposed to vibration

Tests of autonomic nervous function were conducted on 38 workers who had been exposed to vibration [16: VWF(+) group, 22: VWF(-) group, VWF: vibration-induced white finger] and 17 workers who had not been exposed to vibration (control group). Measurements were made of R-R interval variation of the electrocardiogram at rest and during deep breathing, and serum dopamine-beta-hydroxylase (DBH) activity during an immersion test of the hand in 10 degrees C water. Heart-rate variation related to respiratory arrhythmia indicates parasympathetic activity, and serum DBH activity is regarded as an indicator of sympathetic activity. The variations in the R-R interval during deep breathing were smallest in the VWF(+) group, followed by the VWF(-) group (P less than 0.05 and P less than 0.01, compared with the control group). The DBH activity of the VWF(+) group was larger than those of the VWF(-) group and the control group, however, the differences were small and not statistically significant. The reduced R-R interval variations in the VWF(+) and the VWF(-) groups support the hypothesis that autonomic nervous function can be affected by exposure to vibration. The change of DBH activity induced by cold exposure may be an unsuitable index of sympathetic tone. Further study of the autonomic nervous function in workers with vibration syndrome is recommended.     

手传振动作业工人手部温度分布的红外图像分析及其冷水负荷试 …

目的 研究手传振动作业工人手部温度分布及基冷水负荷试验的影响。方法 应用ＫＹ－３３３型远红外摄像仪,对５０名手传振动作业工人和２７名健康对照工人,在１０℃、１０ｍｉｎ冷水试验前后进行手部红外摄像。结果 白指病人、接振工人和对照工人在冷水试验前后不同手指之间及左右手相应手指之间皮肤温度比较,差异均无显著性。白且各手指皮温在冷水试验前后,除冷试后即刻外,无显著低于接振组和对照组,接振组各手指的皮温在冷     

Laser Doppler imaging of skin blood flow for assessing peripheral vascular impairment in hand-arm vibration syndrome

The objective of this study was to evaluate the usefulness of laser Doppler imaging (LDPI) of the skin blood flow for assessing peripheral vascular impairment in the hand-arm vibration syndrome (HAVS). The subjects were 46 male patients with HAVS, aged 50 to 69 yr, and 31 healthy male volunteers of similar age as controls. A cold provocation test was carried out by immersing a subject's hand on his more severely affected side into cold water at a temperature of 10 degrees C for 10 min. Repeated image scanning of skin blood flow of the index, middle, and ring fingers was performed every 2 min before, during, and after the cold water immersion using a PMI-II laser Doppler perfusion imager. The mean blood perfusion values in the distal phalanx area of the fingers were calculated on each image. The patients suffering from vibration-induced white finger (VWF, n=20) demonstrated significantly lower skin blood perfusion at each interval of the test as compared with those without VWF (n=26) and the controls (p<0.01, ANOVA). The blood perfusions in the HAVS patients were associated with the severity of the symptoms as classified by the Stockholm Workshop scale for vascular staging. When a subject was considered to be positive if any of the tested fingers showing a decreased blood perfusion and/or a delayed recovery pattern, the sensitivity was 80.0%, and the specificity was 84.6% and 93.5% for patients without VWF and the controls, respectively. These results suggest that the LDPI technique could provide detailed and accurate information that may help detect the existence of impaired vascular regulation to cold exposure in the fingers of workers exposed to hand-transmitted vibration.     

Epidemiological survey of shipyard workers exposed to hand-arm vibration

Summary All 169 caulkers employed at a ship yard were examined to determine the prevalence of vibration syndrome due to pneumatic portable tools (chipping hammer and grinders).Vibration measurements and medical investigations were performed in the field between September 1977 and July 1978.Vibration spectra recorded on pneumatic tools were compared to ISO Draft Proposal No. 5369. The chipping hammer produced the highest acceleration levels and exceeded the maximum ISO limits even for a short exposure time (30 min per shift).The results of medical investigations pointed out that 78.7% of caulkers experienced paresthesia in their hands, 31.3% Raynaud's phenomenon (or VWF), 20.1% presented with radiological signs of osteoarthritis at wrist and shoulders, 10.0% with olecranon exostoses, and 31.3% with cysts of the carpal bones.To diagnose VWF the skin temperature of the hands were recorded in all 169 caulkers and 60 controls at the shipyard. The basal skin thermometric map (recorded in 16 positions per hand) demonstrated an average difference of 2–2.5°C between the two populations.The thermometric curve, monitored every 3 min for 40 min after a provocative cold-test (immersion of hands and wrists in melting ice for 2 min), well differentiated workers exposed and not exposed to vibrations.The authors emphasize that skin temperature (before and after the coldtest) are suitable for epidemiological purposes to compare the prevalence rates of VWF in control-experimental groups.The results of this study were presented at the International Symposium on Man Under Vibration, Suffering, and Protection, Udine (Italy), 3–6 April 1979     

Prevalence of Raynaud's phenomenon in different groups of workers operating hand-held vibrating tools

In eight groups of subjects operating various hand-held vibrating tools and aged from 30 to 59 years, the prevalence rates of vibration-induced white finger (VWF) and numbness, pain, or stiffness in the upper and lower extremities were investigated. Hand-transmitted vibration levels (HTVLs) were measured on the back of the hand, by means of unidirectional (x-axis) vibration dosimeters, and the frequency-weighted acceleration levels [(L_h,w)_eq,t] were determined as the vibration levels. The prevalence rates of VWF and numbness of the hands in these subjects were compared to the prevalence rates of Raynaud's phenomenon (RP) and numbness of the hands in 1027 males and 1301 females not occupationally exposed to vibration (age range: 30–59 years). It was observed that in subjects exposed to HTVLs of between 1.1 and 2.5 m/s², the prevalence of VWF was between 0.0% and 4.8%. The prevalence of VWF reached 9.6% in a group of workers exposed to HTVLs of 2.7–5.1 tn/s². The latter group showed a significant difference (P < 0.05) in the prevalence of VWF compared to the 2.7% prevalence of RP in male subjects of the general population. The prevalence of VWF in female subjects exposed to vibration (4.3%) was not significantly different from the prevalence of RP in females of the general population (3.4%). The prevalence rates of numbness of the hands were in the range of 6.5%–30.4% in the exposed groups and in the range of 13.4%–29.5% in the general population. Among the subjective symptoms, only VWF showed a significant positive correlation with HTVLs (R ² = 0.5, P < 0.05). It was concluded that in decisions concerning quantitative recommendations for vibration exposure, the prevalence of VWF should be employed. With a view to decreasing the risk of developing VWF, estimated vibration safety values for 4 h and 2 h daily exposures are discussed.     

Vibration white finger, digital blood pressure, and some biochemical findings on workers operating vibrating tools in the engine manufacturing industry

A clinical and laboratory investigation was carried out on 76 operators using pneumatic hand grinders and impact wrenches in the engine manufacturing industry. Twenty-two vibration-exposed workers (28.9%) had no symptoms in the hands (stage 0 of the Stockholm Workshop scale), 34 (44.7%) were affected with sensorineural disturbances in the fingers (stage SN), and 20 (26.3%) suffered from vibration white finger (VWF stages 1-2-3). In the vibration-exposed operators and in 30 comparable referents not exposed to vibration, finger systolic blood pressure (FSP) was measured on a test finger and on a control finger after digit cooling to 30 degrees C and 10 degrees C. The results of the cold provocation test were expressed as percent change of FSP by cooling the test finger from 30 degrees C to 10 degrees C (FSP%t, 10 degrees) and as digital/brachial pressure index during local cooling at 10 degrees C (DPIt, 10 degrees). After cold provocation the mean values of FSP%t, 10 degrees and DPIt 10 degrees were more significantly reduced in the vibration-exposed workers with VWF than in those without VWF and the referents (p less than 0.001). The cold provocation test was found to differentiate between VWF subjects with stages 1-2 and stage 3 (p less than 0.02). It is concluded that the measurement of FSP combined with finger cooling is a useful laboratory test to diagnose objectively Raynaud's phenomenon of occupational origin. The vibration-exposed workers and the referents were also tested for serum levels of immunoglobulins and complement and for daily excretion of urinary free catecholamines. Between the reference and vibration groups no differences in the mean values of the immunologic parameters and urinary catecholamines were found. The meaning of these findings is discussed.     

Preliminary study on the assessment of peripheral vascular response to cold provocation in workers exposed to hand-arm vibration using laser Doppler perfusion imager

Measurements of changes in finger skin blood flow with laser Doppler perfusion imaging (LDPI) in response to cold provocation test (10 degrees C, 10 min) were performed in 12 men suffering from vibration induced white finger (VWF) and 13 exposed controls. The mean perfusion values in both groups reduced markedly as a result of immersion of the hand in cold water. In the controls, however, the mean value increased gradually until the end of the cold provocation, while that in the VWF subjects remained at the lowest level. After removal of the hand from the cold water, the skin blood perfusion in the controls recovered rapidly and nearly reached the baseline value. In the VWF subjects, it had a slight increase immediately following the cold immersion but no tendency to rise as the time span increased. Analysis of covariance controlling for possible confounders revealed that the VWF subjects had significantly lower perfusion values compared to the controls in the last several minutes of the cold provocation and the following recovery. These findings suggest that the LDPI technique enables visualizing and quantifying the peripheral vascular effects of cold water immersion on the finger skin blood perfusion and thus has the potential of providing more detailed and a&curate information that may help detect the peripheral circulatory impairment in the fingers of vibration-exposed workers.     

Correlation between vibration-induced white finger and symptoms of upper and lower extremities in vibration syndrome

Summary The correlation was investigated between the frequency of attacks of vibration-induced white finger (VWF) and numbness or coldness of the fingers and legs in patients with vibration syndrome. Some 1687 patients with vibration syndrome were examined and of these 342 chain-saw operators and 277 rock-drill operators had no disease other than vibration snydrome. Then subjects were matched by age and period of treatment within three years. In the last analysis, 20 in the VWF almost everyday group or in the never group, and 40 in the occasionally group were selected from the chain-saw operators, and from the rock-drill operators 32 in the VWF everyday or the never group and 64 in the occasionally group. The present study showed that, with the frequency of VWF attacks, patients had a higher prevalence of coldness not only in the fingers but also in the legs. These findings suggest a correlation between the severity of circulatory disturbances of the upper extremities and that of the lower ones in patients with vibration syndrome. Further studies on circulatory disturbances in the leg are required.     

Raynaud's phenomenon of fingers and toes of miners exposed to local and whole-body vibration and cold

Summary In a study of 27 underground miners exposed to hand or whole-body vibration, cold or other vasoconstrictive environmental factors, higher prevalences of Raynaud's phenomenon in both fingers and toes were found than in a control group not exposed to vibration. There were no Raynaud-like phenomena among miners not exposed to vibration. There was a positive correlation between the two locations. This may mean a general susceptibility of vasospasm, but it seems more probable that the disorders are caused by vibration exposure to fingers and toes.     

A Cross Sectional Study on Hand-arm Vibration Syndrome among a Group of Tree Fellers in a Tropical Environment

This study aimed to explore the clinical characteristics of hand arm vibration syndrome (HAVS) in a group of tree fellers in a tropical environment. We examined all tree fellers and selected control subjects in a logging camp of central Sarawak for vibration exposure and presence of HAVS symptoms utilizing vibrotactile perception threshold test (VPT) and cold water provocation test (CWP). None of the subjects reported white finger. The tree fellers reported significantly higher prevalence of finger coldness as compared to the control subjects (OR=10.32, 95%CI=1.21–87.94). A lower finger skin temperature, longer fingernail capillary return time and higher VPT were observed among the tree fellers as compared to the control subjects in all fingers (effect size >0.5). The VPT following CWP of the tree fellers was significantly higher (repeated measures ANOVA p=0.002, partial η²=0.196) than the control subject. The A (8) level was associated with finger tingling, numbness and dullness (effect size=0.983) and finger coldness (effect size=0.524) among the tree fellers. Finger coldness and finger tingling, numbness and dullness are important symptoms for HAVS in tropical environment that may indicate vascular and neurological damage due to hand-transmitted vibration exposure.     

Development of an improved system for monitoring the peripheral circulation and its application. Part 2. Its application to the cold water immersion test in workers using vibratory tools

Using an improved system for measuring skin blood flow by the thermal clearance curve, the change of the skin blood flow in the finger (finger blood flow) of the workers using vibratory tools induced by 10 degrees C cold water immersion for 10 min was observed in order to clarify the pathogenesis of vibration-induced white finger (VWF) from the aspect of peripheral circulatory function and simultaneously to demonstrate the efficiency of the system. The subjects constituted a group of 10 workers with VWF (VWF group) and 10 healthy workers without a history of hand-arm symptoms (control group). Ages and years of exposure to vibration in the two group were almost equal. The results were as follows. 1) While the finger blood flow in the control group was remarkably decreased at 1 min after the immersion, the decrease in the VWF group was low as compared with that in the control group. This result shows that vasoconstriction just after the immersion in VWF patients is not as great as that in the control group. 2) The finger blood flow in the control group at 5 min after the immersion was increased. In contrast no increase in the VWF group was observed. These results showed that cold-induced vasodilatation (CIVD) in VWF patients diminished. 3) An increase of the finger blood flow at 1 min after stopping the immersion was observed in the VWF group. These results suggest that the property of reaction to cold in VWF patients is not excessive vasoconstriction as has been hypothesized, but the diminution of CIVD. Apart from 10 workers of VWF group, observing the change of the finger blood flow in a case in which VWF was provoked by the immersion, the author found an abnormal decrease of the finger blood flow at 5 min after the immersion. This finding supports the hypothesis that the diminution of CIVD plays an important role in VWF attack as well. Concerning the characteristics of peripheral circulatory function in VWF patients, it can therefore be considered that its reaction in VWF attack is vasospasms, while the reaction to cold is the diminution of CIVD in the non-attack phase. The cold water immersion test using the system was recognized to be useful for diagnostic examination because the estimation of finger blood flows at both measuring points, 1 min and 5 min after the immersion, could fairly well discriminate VWF patients from healthy workers.(ABSTRACT TRUNCATED AT 400 WORDS)